ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 181 



He considers that the plankton-algse show no special endemism, but 

 are more or less cosmopolitan. He draws attention, however, to the 

 occurrence of Anabwna as characteristic of tropical waters, and he 

 divides the ij^enus into Euanahaena and Anal senop sis ^ the former section 

 having intercalary, the latter terminal heterocysts. Notes are given on 

 the special plankton of the respective ponds of Sawa, followed by the 

 systematic account of all the species recorded. Critical notes are often 

 appended, and novelties are described and figured. 



Eucapsis, a new Genus of MyxophycesB.* — F. E. Clements and H. 

 Le Roy Shantz describe and figure a new genus of blue-green algag — 

 Eucapsis, allied to Merismopedium and analogous to Sarcina. The 

 species is Eucapsis alpina, and it occurs in a lake on Bald Mountain, 

 Colorado. The cubical floating colonies consist of about 32-512 cells, 

 immersed in a colourless gelatinous matrix. 



Radiofilum.t — J. Brunnthaler gives an account of the genus Radio- 

 fllum and its history. It is characterized by its gelatinous sheath, which 

 has a radial structure. The cells are spherical or ovoid, and possess 

 one to two pyrenoids and a nucleus. The plant has mostly been referred 

 to the Ulotrichace^ and to the Tetrasporacege, l)ut all its characters 

 tend to show it to be a Desmid. It should stand in the sub-family 

 Placodermeae, near Desmidium. It contains three species. 



Gloeotsenium.J — E. N. Transeau writes an account of the life- 

 history of Gkeotsejiium, which he has studied for seven months under 

 culture. He gives first a short history of past work on the genus, and 

 then describes his own results. The mature plant may occur as one- 

 celled individuals, and as two-, four-, and eight-celled families. The 

 first of these types is comparatively rare ; the last exceedingly so. 

 Each of the four types is described. The mature colonies do not 

 divide, that is, the two-celled mature colonies do not form four-celled 

 colonies directly. The size of the family is determined by the number 

 of divisions that take place within the aplanospore. The author con- 

 siders that zoospore-production is improbable. He places the genus 

 near Oocystis, among the Scenedesmacese, and draws up a new generic 

 diagnosis. 



Hgematococcus pluvialis.§— H. C. Jacobsen gives an account of 

 the necessary conditions of cultur*^ of Bsematococcus pluvialis. This 

 species is of common occurrence, but only in favourable conditions. 

 For its inorganic, autotrophic nutrition N, P, S, K, and Mg are neces- 

 sary ; Ca acts adversely on it. It grows only in solutions having a 

 slight salt-concentration, and is very sensitive to acid and alkali. 

 Soluble combinations of heavier metals act on the whole unfavourably 

 on the reproduction. The formation of the red colour is brought 

 about by several factors, which are discussed. The haematochrome, 



* Minnesota Bot. Studies, iv. (1909) pp. 133-5(1 pi.). 

 t Oesterr. Bot. Zeitschr., Ixiii. (1913) pp. 1-8 (figs.). 

 X Bot. Gaz., Iv. (1913) pp. 66-73 (1 pi. and figs.). 

 § Folia Microbiol. Delft, i. (1912) 35 pp. 



